When is a runner considered to have acquired the right to an unoccupied base?

A runner is considered to have acquired the right to an unoccupied base when they reach that base without being tagged by a defensive player. This principle is rooted in the fundamental rules of baseball, which state that a player legally gains ownership of a base when they touch it, provided they are not put out by a tag or force out at that base.

In the context of the game, this emphasizes the importance of base running techniques and the role of umpires in making decisions on whether a runner safely reaches a base. The act of reaching the base safely allows the runner the right to that base until they are legally challenged by the defense, such as being tagged out or forced out.

Understanding this rule is critical for both players and umpires, ensuring that fair play is maintained and that runners can advance safely. The other options would either misinterpret the situation or relate to various scenarios that do not reflect the direct action of legally acquiring the base.